(a) Field of the Present Invention
The present invention discloses a bi-directional power such as AC power or periodically alternated power which is provided to a capacitive impedance component and an inductive impedance component in series connection, whereof their series resonance frequency is in series resonance status with the frequency or period of the bi-directional power source, whereof the bi-directional divided power produced across the two ends of the capacitive impedance component or the inductive impedance component is rectified through a rectifier device to a DC power, whereby to drive the uni-directional conducting light emitting diode, or to drive at least two rectifier devices which are respectively parallel connected across the two ends of the first and second impedances while the AC powers of the first and second impedance are respectively rectified through the said rectifier devices to the DC power outputs, thereby to drive the uni-directional conducting light emitting diodes individually.
When in the high frequency bi-directional power applications, the uni-directional light emitting diode drive circuit in bi-directional power series resonance of the present invention can effectively reduce the volume and weight of the circuit as well as lower the cost.
(b) Description of the Prior Art
The conventional light emitting diode drive circuit using AC or DC power source is usually series connected with current limit resistors as the impedance to limit the current to the light emitting diode, whereof the voltage drop of the series connected resistive impedance always result in waste of power and accumulation of heat which are the imperfections.